Behavioural Plasticity, Metabolomics and Social Transitions in Spiders – MetaSpi

Sociality is present in all lineages and represents a major evolutionary transition. The maintenance of social cohesion in juveniles at advanced stages is considered the main pathway for the emergence of permanent sociality. Spiders are relevant models for exploring the mechanisms involved in social transitions. The vast majority of the 52,000 known species are solitary as adults, but transient gregariousness is a universal feature of spider life history, and there are 19 species of social spiders, making this taxon valuable for initiating comparative studies. Our previous work has shown that loss of tolerance in solitary spiders is a consequence of isolation after dispersal, as juveniles reared alone are aggressive while those reared in groups are tolerant. This project combines behavioural approaches with metabolomics to decipher the physiological mechanisms involved in the expression of sociality in spiders. Our hypothesis is that the transition to permanent sociality would have been accompanied by a loss of plasticity in the regulation of signalling pathways controlling the expression of social tolerance. To test this hypothesis, we will compare the metabolomes of spiders of two solitary species and two social species reared alone and in groups during ontogeny. We predict that the metabolomes of solitary spiders will show more variation in response to social isolation and ontogeny than those of social spiders. We will then determine the identity of metabolites that are strongly associated with changes in social tolerance in solitary spiders. Once identified, we will manipulate the levels of these candidate metabolites in solitary spiders to reverse their social phenotypes and thereby establish causality. Our project will represent a significant advance in understanding the physiological and behavioural mechanisms associated with social transitions in spiders, both at the ontogenetic and phylogenetic levels.